Furnace having water-cooled grate



' June 12, 1934.

F. E. STOLLER 1,962,791

FURNACE HAVING WATER COOLED GRATE Filed July 2, 1932 2 Sheets-Sheet 1 jille'iziai' fizz m June 12, 1934. F. E. STOLLE'R 1,962,791 FURNACE HAVING WATER COOLED GRATE Filed July 2, 1932 2 Sheets-Sheet Patented June 12, 1934 UNITED STATES PATENT OFFICE 2 Claims.

Difficulty is encountered when burning petroleum coke and coals having a high sulphur content on ordinary grates, because of the formation of molten slag that stops up the air spaces and causes the grates to burn out quickly. The object of the present invention is to produce a simple and novel furnace construction and grate therefor which will permit petroleum coke and coal having a high sulphur content to be burned without producing any injurious effect on the grate.

The various features of novelty whereby my invention is characterized will hereinafter be pointed out with particularity in the claims; but,

for a full understanding of my invention and of its objects and advantages, reference may be had to the following detailed description taken in connection with the accompanying drawings, wherein:

Figure 1 is a front elevation of a steam boiler equipped with a furnace embodying the present invention; Fig. 2 is a vertical section through the boiler setting and furnace, on a larger scale than Fig. 1, looking forward; Fig. 3 is a detail showing the handle end of one of the clinker dumping rods in full lines and in dotted lines, representing the normal position and the dumping position, respectively; Fig. 4 is a horizontal section through the furnace and boiler setting, on the same scale as Fig. 1; the section being taken approximately on line 44 of Fig. 5,-

fragments of the grate and of one of the clinker-supporting gates being broken away; Fig.

5 is a vertical longitudinal section, showing also fragments of the boiler; and Figs. 6 and '7 are, respectively, an edge View and a side View of one of the clinker breakers, the shaft and the separable half of the hub being shown in dotted lines in Fig. 6.

Referring to the drawings, 1, 2 and 3 represent the side walls and the front wall of a boiler setting or furnace, and 4 represents a boiler supported at such an elevation as to provide below the same a furnace chamber. At the rear 'end of the furnace chamber is the usual bridge wall 5. The grate extends downwardly and rearwardly from a point below the fire door 6 to a point lying at a considerable distance in front of the bridge wall. The grate is made hollow so as to permit water to be circulated through the same. I have found that the grate may advantageously be constructed of simple, pure wrought iron piping, sections of which form headers between which extend smaller pipe sections to form the grate bars. I have also found that excellent results are obtained by welding the pipe sections together. In the drawings 1' have shown the grate as composed of two sections arranged side by side, each section being I composed of front and rear headers, 7 and 8 and four smaller pipes 9, 9 constituting the grate bars. In actual practice the grate bars are placed close together and, therefore, the headers of a sectional grate must be so shaped that, when corresponding headers abut, the space be- 653 tween the grate bars of one section and the bars of the other is the same as the space between" any two bars. Therefore, I close the ends of the pipe sections forming the headers by means of disks 10, as shown in Fig. 2, fitting within the headers and welded to the surrounding cylindrical walls. The two grate sections are supported on parallel inclined beams 11, 11 secured to the side walls 1 and 2, together with a central longitudinal beam 12. The beams 11 and 12 are conveniently supported by horizontal angle irons 13 and 14 secured to the inner side of the front wall 3 and to the front side of the bridge wall 5. The members 13 and 14 are preferably provided at the middle with bearing seats 15, 15 to receive projections 16,' 16 on the ends'of the bar 12, so as to insure that this bar will not slip sidewise. The' beams 11 may or may not be secured to the side walls of the furnace. In the upper edge of'each of the beams 11 and 12, in position to receive the adjacent end of the corresponding rear header, is a bearing seat 17. The front headers may rest directly on'top of the beamsbut, by fitting the rear headers into seats in the supporting beams, the grates will be held against accidental shifting in the longitudinal direction. Extending across the tops of the beams 11 and v 12, just in front of the angleiron 14, is a round rod or shaft 18 on which are hung two gates 19 and 20; each gate being slightly shorter than the distance between the central beam and one of the side beams, and being wide enough to extend into proximity to the rear edge of the grate. Each gate has fixed thereto, near the front end thereof, a depending rigid arm 21 to the lower end of which is hinged the rear end of an operating rod 22 extending out through the front wall of the furnace and having at its outer end a handle or grip 23. As best shown in Fig. 3, the rod 22 is abruptly widened near its outer end to form a rearwardly-faced shoulder 24. When this shoulder engages the outer face of the front wall of the furnace, just below the hole through which the rod passes, as shown in full lines 'of, a slot 31.

' beams.

in Fig. 3, the corresponding gate is locked in its raised position, as shown in full lines in Fig. 5. When the free end of the rod is lifted and the rod pushed back, as indicated in dotted lines in Fig. 3, the corresponding gate will be swung down, as indicated in dotted lines in Fig. 5, thereby causing clinker that may have been resting on the grate to be dropped down into the ash pit.

The grate is kept cool by water flowing through the same. To this end, I have connected each of the rear headers 8 to a low point on the boiler by suitable piping 26 and have connected each of the headers '7 to the boiler at about the water line by means of suitable piping 27. When there is a fire on the grate, causing heat to be transmitted to the water within the same, the inclination of the grate insures rapid circulation, since the warm water will naturally flow uphill from the rear end of the grate toward the front end and thence into the upper part of the boiler.

I have found that, where the grates are made of black iron pipe sections and the burning fuel and the molten slag reach a temperature of 2500 or 3000", this temperature has so little effect on the grate that after months of operation the grate will retain its initial black appearance. This is, of course, in the case of furnaces in which there is an up-draft through the grates. Furthermore, the slag does not freeze to the grate and choke the air inlets, but remains in such a condition that the resulting clinker may easily be removed from time to time by a suitable slice bar or clinker breaker means.

For the purpose of removing the clinker from y the grate, I provide a plurality of plate-like slice bars mounted underneath the grate in such a manner that they may be moved up through the spaces between the bars and rearwardly; thus breaking up the clinker and then pushing it back onto the dumping gates or plates. Most of the clinker forms on the rear halves of the grates, and therefore it will usually be sufficient to have asingle set of slicebars or clinker breakers that will operate throughout the rear half of a grate. In the arrangement shown, there are two sets of these slice bars, one underneath the rear half of the grate and the other underneath the front half. Each slice bar is shown as taking the form of a substantially semi-circular plate 30 into which extends, substantially parallel with the straight edge there- Fixed to the semi-circular plate at the inner end of the slot, is one half 32 of a hub divided into two halves on a longitudinal plane. Extending across the space between the central beam 12 and each of the beams 11, toward the rear of the grate and underneath the grate, is a rotatable shaft 33 which may conveniently be square in cross section except at the ends which are cylindrical so as to be rotatable in suitable bearings in the supporting As many of the semi-circular plates as there are air passages in each of the grate sections, are slipped upon each of the shafts 33 until the shafts are engaged in the half-hubs 32. Then complementary hub members 34 are placed against the opposite sides of the shafts tion or removed; and it may be quickly and easily adjusted so as to be brought properly into alignment with the air space through which it is to play.

Normally the slice bars or clinker breakers lie below the grate in the position shown in full lines in Fig. 5. Upon turning the shafts 33 in the clockwise direction, as viewed in Fig. 5, the long ends of the plates swing up through the spaces between the grate bars and then down until they engage with the rear header 8. During this movement, the plates first press up on any clinker that may be overlying the grate, tearing it loose from the grate, if it should be adhering thereto even slightly, and then throwing it back upon the clinker-receiving gates. It will be seen that the curved edges of the plates are the advance edges during the return strokes of the breaker plates, so that they will ride underneath and through the bed of fuel without driving the fuel down into the ash pit as would be the case if these edges were straight or concave instead of convex and could therefore obtain a purchase on the fuel.

The forward or upper set of slice bars or clinker breakers are like those that I have just described, and they are mounted on rotatable transverse shafts 36, 36 similar to the shafts 33.

The shafts 33 and 36 may be turned in any suitable manner. In the arrangement shown, each of the shafts 33 has fixed thereto a radial arm 37, and each of the shafts 36 is provided with a similar arm 38. Each arm 3'7 is pivoted or hinged to the inner end of an actuating bar 39, whereas each arm 38 is pivoted or hinged to the upper end of a rigid arm 40 rising from the bar 39. Each bar 39 extends out through the front wall of the furnace and is there connected to a lever 41. Normally the lever stands upright, as shown in full lines in Fig. 5, the slice bars or breaker plates being in their idle positions. When it is, desired to remove the clinker from the grate, the levers 41 are swung out into the positions shown in dotted lines in Fig. 5 so as to operate the slice bars or clinker plates through a working stroke. Then, after the clinker has been deposited upon the dumping gates, these are dropped down, as heretofore explained, completing the cleaning operation Without making it necessary to disturb the fire by poking or slicing it with bars or other implements inserted through the fire door.

It will thus be seen that by makinga hollow grate of pure wrought iron piping welded together, placing it in the fire box or furnace with a sharp downward inclination toward the rear, connecting the low end of the grate to a low point on the boiler and the high end of the grate to the boiler at about the water line, permitting the air to support combustion to come up through the grate, and providing simple means to break up the clinker and move it rearwardly from the grate: I have produced a furnace of the up-draft type which may be built at a comparatively low cost, will successfully burn fuels which it has heretofore been almostimpossible successfully to burn in this type of grate because of the difiiculty of keeping the grates clean and the air passages open, and which will last almost indefinitely instead of burning out in a short time as do other grates when petroleum coke or coal having a high sulphur content is being burned.

There are some coals of very low ash content,

and it is diflicult, also, to burn coals of this kind on ordinary grates. Although the reason why coals of this type cannot be effectively burned on the ordinary grate is not the formation of slag as in the case of fuels to which I have heretofore referred, I have found that my improved grate will successfully burn coal that has very little ash.

While I have illustrated and described with particularity only a single preferred form of my invention, I do not desire to be limited to the exact structural details thus illustrated and described; but intend to cover all forms and arrangements which come within the definitions of my invention constituting the appended claims.

I claim:

1. The combination with a furnace, of parallel beams extending downwardly and rearwardly therein from the front end thereof, a grate overlying the beams and spanning the space between them, said grate being composed of transverse tubular headers at the front and rear ends and hollow grate bars extending between and connecting the headers, seats for the headers at the tops of the beams, and said headers resting loosely upon said seats so as to permit the grate to be removed by simply lifting it off the beams.

2. The combination with a. furnace, of transverse cross beams at'the front and rear ends, within the furnace chamber, the forward cross beam being at a higher elevation than the rear cross beam, of longitudinal beams resting at their front and rear ends on said cross beams,

'a grate overlying the longitudinal beams and spanning the space between them, said longitudinal beams having seats in the upper edges thereof, and elements on the grate resting in said seats and holding the grate against longitudinal movement with respect to the furnace.

FRED E. STOLLER. 

